Generator and method for generating controlled frequencies

Abstract

To provide a frequency generator for generating a controlled frequency, an improving method therefor, a program, and a frequency generator system.SOLUTION: A frequency generator 300 comprises frequency ratio generators 100, 101, 102, a comparator 310, and a controlled oscillator 330 and has, as input, a controlled frequency 331. The controlled frequency is a generated frequency and thus effectively output of the frequency generator. The frequency ratio generators provide a frequency ratio signal 312. The frequency ratio generators comprise a resonator, determine a ratio between the controlled frequency and a resonance frequency of the resonator, and determine a ratio between two resonance frequencies of the resonator. At least one of the resonance frequencies is an overtone frequency. The comparator has, as input, the frequency ratio signal and a target ratio 311; compares the frequency ratio signal to a target ratio; and provides, as output, a comparison signal 315, which is the result of this comparison.SELECTED DRAWING: Figure 1

Description

Detailed Description of the Invention ,

[0006] ,

[0001] [Field of the Invention] The present invention relates to the field of generators and methods for generating a controlled frequency that is highly stable in frequency.

[0002] [Background of the Invention] Generating a signal having a controlled frequency can be a useful electronic component in a variety of electronic circuits with a wide variety of functionality.

[0003] [[ID=十六]]Known circuits for generating frequencies are known from WO2013 / 066161A1, specifically FIG. 2.

[0004] WO2013 / 066161A1 includes a first oscillator for supplying a first oscillation signal, a second oscillator for supplying a second oscillation signal, a first controller for delivering a first control signal as a function of the phase difference between the first controller input and the second controller input of the first controller, and a second controller for delivering a second control signal as a function of the phase difference between the first controller input and the second controller input of the second controller, a resonator, at least one second resonance frequency with a first phase shift that depends on the difference between the frequency of the second excitation signal and the second resonance frequency, and processing means for receiving the first oscillator signal and the second oscillator signal, determining their mutual ratio, looking up a frequency compensation factor in a pre-stored table, and outputting a compensated oscillation signal.

[0005] In FIG. Two of WO2013 / 066161A1, the divider setting of the feedback divider determines the ratio between the resonator frequency and the frequency output. <0XXXXX19> A disadvantage of the circuit in Figure 2 of WO2013 / 066161A1 is that the frequency is not controllable. Furthermore, another disadvantage is that the circuit has only one feedback loop. With only one feedback loop, all noise sources in that loop contribute to the phase noise of the output frequency. Therefore, the loop filter in this circuit must strike a trade-off between a high bandwidth to track changes in the loop and a low bandwidth to attenuate all noise sources in the loop.

[0007] U.S. Patent Application Publication 2014 / 152354(A1) discloses a method for forming an output signal by adjusting the frequency of a generated signal, comprising: forming the generated signal in a signal generator; comparing a feedback signal with a reference signal and generating a control signal in accordance with the comparison, wherein the feedback signal is generated using the output signal; and generating an output signal by performing a frequency division operation in accordance with the generated signal and a division coefficient, wherein the division coefficient is specified in accordance with the control signal. A disadvantage of U.S. Patent Application Publication 2014 / 152354(A1) is that the output signal may have phase noise, thereby rendering the method unsuitable for the requirements.

[0008] [Overview of the prefecture] The object of the present invention is to overcome one or more of the disadvantages described above.

[0009] According to a first aspect of the present invention, a frequency generator for generating a controlled signal having a controlled frequency, - Includes a frequency ratio generator that is tuned to produce frequency ratios, and the frequency ratio generator is - An input configured to receive a controlled signal, - A first controlled frequency divider (110) is tuned to generate a first divided signal (115) having a first divided frequency which is a controlled frequency divided substantially by a first frequency ratio signal, - A converter tuned to generate an excitation signal (129) having a first divided frequency based on a first divided signal, wherein the excitation signal is supplied to a resonator for excitation of the resonator, - A connector for connecting to a resonator tuned to generate a resonant signal having a first resonant frequency, wherein the resonator is excited based on a controlled signal, - Includes an output configured to provide a frequency ratio signal based on a first frequency ratio signal that shows the frequency ratio between a controlled frequency and a first resonant frequency, The frequency generator further, - A comparator that is tuned to generate a comparison signal based on a comparison of the frequency ratio with the target ratio, - A frequency generator including a controlled oscillator circuit that is tuned to produce a controlled signal having a controlled frequency based on a comparison signal.

[0010] A frequency ratio generator outputs a frequency ratio signal. The frequency ratio signal represents the frequency ratio between a controlled frequency and a first resonant frequency. A resonator provides a relatively stable or fixed resonant frequency, which cannot be controlled over a wide range of frequencies. A controlled oscillator, on the other hand, can provide such a wide range of frequencies, or it is impossible to control them at all. The frequency ratio can be set to a controlled ratio using the target ratio according to the present invention. Therefore, the present invention offers the advantage of a controlled signal having a controllable frequency over a wide frequency range.

[0011] The target ratio can be set to any positive rational number. For example, forward error correction in telecommunications requires additional bits to be inserted or extracted from a bitstream. Both bitstreams have separate frequencies, and therefore typically their own clock signals. These clock signals are typically non-integer multiples of each other. This frequency generator advantageously allows for the generation of non-integer ratios between the controlled frequency and the resonant frequency.

[0012] Comparators handle relatively low-frequency signals. These signals have a relatively small bandwidth, above DC. Therefore, comparators can be implemented in a DSP or CPU, offering the advantage that additional functionality can be easily implemented without direct hardware impact. Thus, this frequency generator has the advantage of being highly adaptable to new or additional functionality.

[0013] For a detailed description of the frequency generator used as an element in this invention, refer to the document filed as patent application NL2022646. This document is incorporated herein by reference in its entirety. Specifically refer to the embodiments in this document that incorporate a resonator. Also, specifically refer to the definitions and scope that apply to this invention.

[0014] The controlled signal is typically 8kHz to 24MHz, preferably 10kHz to 22MHz. The low-phase noise signal is in the frequency range of MHz, more preferably 12kHz to 20MHz, most preferably 14kHz to 18MHz, and less than 500fs, preferably 200fs, more preferably 100fs, most preferably 80fs.

[0015] In one embodiment of the present invention, the frequency generator is - Includes an outer loop filter that is tuned to generate a filtered comparison signal based on the comparison signal, The controlled frequency is determined based on the filtered comparison signal. The outer loop is formed by a frequency ratio generator, comparator, comparison signal, outer loop filter, filtered comparison signal, controlled oscillator, and controlled signal. The outer loop filter filters the comparison signal, thereby preventing instability in the outer loop.

[0016] Loop instability can be detected from the unstable controlled frequency of the controlled signal. Typically, a frequency ratio generator has an inner loop, which is a low-pass filter with a cutoff frequency. The outer loop filter is typically also a low-pass filter. Furthermore, the cutoff frequency of the outer loop is chosen low enough to remove the maximum amount of noise, allowing the controlled oscillator to generate the controlled signal with minimal phase noise. On the other hand, the cutoff frequency should be chosen high enough to allow changes in the outer loop due to, for example, temperature changes or hysteresis to be tracked, thereby keeping the controlled frequency stable. Furthermore, the cutoff frequency should be chosen high enough to minimize the startup delay. Both loop filters typically also have integrated behavior in addition to proportional behavior. Integrated behavior in static situations or stable modes means that the loop in which the loop filters are part no longer exhibits residual error, which is advantageous as it increases the accuracy of achieving the target ratio.

[0017] In one embodiment of the present invention, the comparator includes a subtractor that is tuned to provide a comparison signal based on subtracting a target ratio from a frequency ratio, and / or The comparator includes a divider that is tuned to provide a comparison signal based on the division of frequency ratios by a target ratio.

[0018] The subtractor may include an adder with a signal inverter on one input. The divider may include a multiplier with an inverse value supplied to one of its inputs. The measured ratio is typically compared to a target ratio. The target ratio can be predefined, set, or continuously changed by another feedback loop. The target ratio can be changed temporarily, continuously, or permanently, etc., to match the phase of a controlled frequency to the phase of the resonator's resonant signal.

[0019] As the frequency ratio is controlled, the frequency ratio typically substantially reaches or at least approaches the target ratio during stable operation. Thus, it can be stated as follows. t = target ratio r = frequency ratio

[0020]

Number

[0021] The aforementioned conditions are typically satisfied during stable operation, and the frequency ratio is normalized with respect to the target ratio. Thus, for stable operation, the subtractor and divider with an offset of -1 can be considered the same. The frequency ratio generator, and thus also the behavior of the frequency generator, can be different during startup or power-on, and while compensating for larger disturbances in the frequency generator, especially in separate loops.

[0022] In one embodiment of the present invention, the frequency ratio generator is - a first controlled frequency divider adjusted to generate a first divided signal having a first divided frequency that is a controlled frequency substantially divided by a first frequency ratio signal, - A converter adjusted to generate an excitation signal having a first divided frequency based on a first divided signal, the excitation signal being provided to a resonator for excitation of the resonator, the converter, - A first frequency phase detector adjusted to generate a first phase difference signal based on a first frequency phase difference between the first divided frequency and a first resonance frequency, and a first inner loop filter adjusted to generate a first frequency ratio signal, where a first frequency ratio generator loop is formed by the first control frequency divider, the first divided signal, the first frequency phase detector, the first phase difference signal, the first inner loop filter, and the first frequency ratio signal, and a second frequency ratio generator loop is formed by the first control frequency divider, the first divided signal, the converter, the excitation signal, the resonator, the resonance signal, the first frequency phase detector, the first phase difference signal, the first inner loop filter, and the first frequency ratio signal, The first inner loop filter filters the first phase difference signal, thereby preventing instability of the frequency ratio generator loop.

[0023] The control frequency divider, such as the first control frequency divider, can be a digital control frequency divider. The control frequency divider can be a control multi-frequency divider or a control fractional frequency divider. The frequency phase detector, such as the first frequency phase detector, can be a frequency mixer, an analog multiplier, a digital circuit, or a logic circuit configured as a phase detector. Alternatively, the frequency phase detector can be a digital mixer, such as an XOR port mixer.

[0024] A controlled frequency divider divides the frequency of a first input signal according to a control signal, such as a first control signal. Typically, the control signal is a stabilized signal with low jitter to prevent the introduction of significant additional jitter in the controlled frequency divider. The control signal may include an offset. The divided signals, such as the first divided signal, typically contain jitter or noise introduced by the controlled frequency divider as the dominant noise source.

[0025] A frequency phase detector, which detects the phase between the frequency of a divided signal and the frequency of a second input signal such as a resonant signal, typically also introduces noise. Therefore, the value (such as the height) of the phase difference signal is typically dominated by the phase difference and typically includes the noise introduced by the control frequency divider and frequency phase detector.

[0026] Loop filters, such as the first loop filter, filter phase difference signals. The output signal of a loop filter is a control signal, which represents a frequency ratio. Loop filters are typically low-pass filters. The cutoff frequency of a loop filter is chosen based on two limitations. If the cutoff frequency is chosen too low, the loop will react too slowly to disturbances in the loop, causing loop instability. If the cutoff frequency is chosen too high, the loop will not adequately remove noise in the phase difference signal, which can also cause loop instability. Loop instability can be detected from an unstable control signal. An unstable control signal may have a signal value that fluctuates from one end of the range to the other, or it may stagnate at one end. The cutoff frequency is typically chosen low enough to remove the maximum amount of noise from the phase difference signal while still allowing the control signal to adapt quickly enough to any disturbances introduced in the loop.

[0027] The frequency ratio generator offers the advantage of extremely stable frequency ratio measurements. The frequency ratio generator according to the present invention has a feedback loop with an integration effect. The integration effect provides the advantage of 20 dB / decade rejection of low-frequency noise related to phase. In the frequency domain, this effect results in a 40 dB / decade rejection, while known systems only have a 20 dB / decade rejection.

[0028] Furthermore, the frequency ratio generator replaces the temperature behavior of filtering components such as loop filters with nearly DC, resulting in a small deviation causing only a slight change in the effective bandwidth, while the actual center frequency remains unchanged. In comparison, what is known in the art is a loop filter, and known loops maintain a specific frequency; therefore, these known loop filters are bandpass filters. If the components of a known loop filter change in value, for example, under the effects of temperature or aging, the center frequency of the known loop filter will change. Thus, the circuit according to the present invention offers the advantage of increased temperature stability.

[0029] This frequency ratio generator has a resonator that provides a resonant signal, and an excitation signal is provided to the resonator based on the divided signal. As will be further detailed below, this circuit has the advantage of not having to conform to the Barkhausen criterion. This non-conformity to the Barkhausen criterion has the effect of reducing phase noise.

[0030] A conventional loop conforming to the Barkhausen standard can be likened to AM signal transmission. The present invention, which does not conform to the Barkhausen standard, can be likened to FM signal transmission. FM signals are known to be less susceptible to disturbances. One such disturbance in the present invention may be small adjacent resonant frequencies. These small adjacent resonant frequencies may even cross over, for example, under the influence of temperature changes. In these cases in particular, not having to conform to the Barkhausen standard offers the advantage of significantly reducing the noise generated by small adjacent resonant frequencies.

[0031] Generating a specific frequency with low phase noise requires a considerable amount of power. The advantage of this frequency generator is that two independent frequencies, namely a controlled frequency and a resonant frequency, are loosely coupled via a frequency ratio, and both are generated with low phase noise without doubling the power, while simultaneously consuming far less power by the circuit.

[0032] In one embodiment of the present invention, the phase difference signal has a magnitude based on the frequency phase difference, such as amplitude or value, and / or the control signal has a frequency ratio, such as amplitude or value. It has a magnitude that indicates [the specified value]. When the phase or control signal is an analog signal, the signal information is typically, advantageously, contained in the signal's amplitude. When the phase or control signal is a digital signal, the signal information is typically, advantageously, contained in the signal's digital value. The digital value may be a binary code, a BCD code, a Gray code, a combination of these codes, or any other code with a defined value system.

[0033] In one embodiment of the present invention, the loop filter is a low-pass filter, which preferably has a cutoff frequency that is advantageously below the frequency noise introduced by the control frequency divider and preferably advantageously above the ratio of the changes in the first and second frequencies. Furthermore, the cutoff frequency should be advantageously selected such that the control signal is within a specified range, while the circuit remains stable under changing conditions that introduce disturbances in the circuit. The specified range is typically specified by the user. The specified range may also be determined based on noise introduced by other functions in the circuit, such as the control frequency divider and frequency phase detector. The specified range may also be influenced by variations in the first and second input signals.

[0034] In one embodiment of the present invention, the controlled frequency divider is a controlled fractional frequency divider. The phase difference between the divided signal and the second input signal may be caused by static phase difference and / or frequency difference and elapsed time. In this embodiment, the use of a controlled fractional frequency divider is advantageous because the first frequency is divided at a higher granularity. Furthermore, because the granularity is higher, the first frequency can be advantageously selected to be lower. The use of high frequencies has disadvantages such as crosstalk and increased energy loss.

[0035] The resonator may be a quartz resonator, and preferably, the resonant frequency is the harmonic resonant frequency of the quartz resonator. The resonator is typically one that allows simultaneous resonance at different frequencies. Quartz is a readily available and straightforward solution for resonators. Harmonic frequencies change in frequency under the influence of temperature in a similar manner to the fundamental frequency. In contrast, harmonic frequencies can change in frequency in different ways under the influence of temperature. Furthermore, different harmonics of quartz can change in frequency in different ways under the influence of temperature. Thus, different harmonics can have different temperature gradients. Since harmonics of quartz can be selected, the circuit can be advantageously designed to have predefined temperature behavior based on the predefined behavior of the resonator.

[0036] As described, the temperature behavior may differ if at least one, preferably two, of the divided frequencies are selected as harmonic frequencies. The temperature can vary in the range of -40°C to +125°C. Within this range, the temperature gradient with respect to a particular harmonic may vary.

[0037] In one embodiment of the present invention, the frequency ratio generator is - A second controlled frequency divider tuned to generate a second divided signal having a second divided frequency which is substantially a controlled frequency divided by a second frequency ratio signal, - A second frequency phase detector, which is tuned to generate a second phase difference signal based on a second frequency phase difference between a second divided frequency and a second resonant frequency, - A second inner loop filter, which is tuned to generate a second frequency ratio signal that indicates a second frequency ratio based on a second phase difference signal, - An adder that is tuned to produce the summed signal supplied to the converter. An adder exists in which the added signals have a first divided frequency and a second divided frequency, - Includes a temperature compensator for compensating for changes in the resonant frequency of the resonator, the temperature compensator is - An input configured to receive a first frequency ratio and a second frequency ratio, - A first divider adjusted to generate a first division value based on the division of a first frequency ratio and a second frequency ratio, - A computer, preferably including a lookup table, that is configured to calculate a compensation coefficient based on one or more values ​​from a group consisting of a first phase difference signal, a second phase difference signal, a first frequency ratio, and a first division value. - A redresser that is tuned to generate a frequency ratio based on correcting a signal based on one or more of a group consisting of a first phase difference signal, a second phase difference signal, and a first frequency ratio, using a compensation coefficient, The excitation signal is based on the summed signal. A third frequency ratio generator loop is formed by a second control frequency divider, a second divided signal, a second frequency phase detector, a second phase difference signal, a second inner loop filter, and a second frequency ratio signal. A second control frequency divider, a second divided signal, a converter, an excitation signal, a resonator, a resonant signal, a second frequency phase detector, a second phase difference signal, a second inner loop filter, and a second frequency ratio signal form a fourth frequency ratio generator loop. The second inner loop filter filters the second phase difference signal, thereby preventing instability in the frequency ratio generator loop.

[0038] The frequency ratio generator loops are in parallel and evaluated simultaneously, and the effect of temperature is measured simultaneously. Known circuits may tend to measure the effect of temperature spaced out over time. This time interval causes temperature inaccuracies in known circuits if the temperature changes over time. Therefore, the ratio generator according to the present invention has the advantage of improved accuracy in temperature measurement.

[0039] In one embodiment of the present invention, the frequency ratio generator is - Includes a selector that is tuned to select one or more groups consisting of a first phase difference signal, a second phase difference signal, and a first frequency ratio, based on one or more values ​​from a group consisting of a first frequency ratio and a first division value. The redresser is tuned to generate frequency ratios based on correcting selected frequency ratios using compensation coefficients.

[0040] This embodiment of the ratio frequency generator advantageously utilizes the resonator's property that it can resonate simultaneously at multiple frequencies. Resonators are typically bulky compared to other elements of a circuit. Therefore, using a resonator to resonate at multiple frequencies allows for circuit integration and miniaturization.

[0041] Furthermore, the selector can advantageously choose the most stable frequency ratio for a given temperature, thereby preventing the frequency ratio from changing significantly due to temperature variations. Additionally, the redresser can base its compensation coefficient primarily on the parameter with the greatest variation in value over a specific temperature range. The parameter can also be used to specify the temperature.

[0042] In one embodiment of the present invention, the frequency ratio generator is - A third controlled frequency which is effectively divided by a third frequency ratio signal A third control frequency divider, which is tuned to generate a third divided signal having divided frequencies, - A third frequency phase detector, which is tuned to generate a third phase difference signal based on a third frequency phase difference between a third divided frequency and a third resonant frequency, - Includes a third inner loop filter which is tuned to generate a third frequency ratio signal that indicates a third frequency ratio based on a third phase difference signal, The added signal also has a third divided frequency, The input to the temperature compensator is further configured to receive a third frequency ratio. The temperature compensator further, - Includes a second divider which is tuned to generate a second division value based on the division of a first frequency ratio and a third frequency ratio, If dependent on Embodiment 6, the selector is further configured to make selections based on a group consisting of a third phase difference signal, a second frequency ratio, and a third frequency ratio, as well as on one or more values ​​from an extended group consisting of a second frequency ratio, a third frequency ratio, and a second division value. The computer is further tuned to calculate a compensation coefficient based on one or more values ​​from the group expanded by the third phase difference signal, the second frequency ratio, the third frequency ratio, and the second division value. The redresser is tuned to generate frequency ratios based on correcting selected frequency ratios using compensation coefficients. A third control frequency divider, a third divided signal, a third frequency phase detector, a third phase difference signal, a third inner loop filter, and a third frequency ratio signal form a fifth frequency ratio generator loop. A third control frequency divider, a third divided signal, a converter, an excitation signal, a resonator, a resonant signal, a third frequency phase detector, a third phase difference signal, a third inner loop filter, and a third frequency ratio signal form a sixth frequency ratio generator loop. A third inner loop filter filters the third phase difference signal, thereby preventing instability in the frequency ratio generator loop.

[0043] This embodiment advantageously allows for the measurement of the hysteresis behavior of a resonator in operation. Known circuits tend to compensate for hysteresis in resonators by designing countermeasures from a theoretical standpoint. Therefore, this embodiment offers the advantage of improved accuracy resulting from hysteresis measurement.

[0044] In one embodiment of the present invention, the selector of the frequency ratio generator is - Selecting one of a group consisting of a first frequency ratio, a second frequency ratio, and a third frequency ratio, wherein the selected ratio is based on one or more values ​​from the group consisting of the first frequency ratio, the second frequency ratio, the third frequency ratio, the first division value, and the second division value, or - Selecting two or more weighted combinations of a first frequency ratio, a second frequency ratio, and a third frequency ratio, wherein the weighted combinations are adjusted to make a selection based on one or more values ​​from a group consisting of the first frequency ratio, the second frequency ratio, the third frequency ratio, the first division value, and the second division value.

[0045] The aforementioned advantages of the selector also apply to this more sophisticated embodiment of the selector. Furthermore, this version of the selector allows for even more balanced combinations with weighted combinations. For example, weighted combinations advantageously allow for the mixing and matching of various performance aspects, such as Alan variance or phase noise.

[0046] In one embodiment of the present invention, the first division value is based only on the first frequency ratio signal and the second frequency ratio signal. The second division value is based only on the first frequency ratio signal and the third frequency ratio signal. The selector is tuned to select one or more of a limited group consisting of a first phase difference signal, a second phase difference signal, and a third phase difference signal, and / or The computer is tuned to calculate a compensation coefficient based on one or more values ​​from a limited group consisting of a first division value and a second division value. This embodiment advantageously limits the amount of selection in the various groups to the signals and / or ratios that are best suited to providing a compensation coefficient, such as with respect to changes in the parameters of various components due to temperature changes.

[0047] In one embodiment of the present invention, the frequency ratio generator includes an analog-to-digital converter tuned to generate a digital resonant signal based on a resonant signal, the digital resonant signal being supplied to at least a first frequency phase sensor. Depending on the operation, manipulating the input signal in the digital or analog domain can be advantageously done in one of those domains. Typically, the resonator is an readily available analog component. More typically, the frequency phase sensor is easier to implement in the digital domain. The ADC advantageously provides a combination of the analog and digital domains, benefiting from availability on the one hand and ease of implementation on the other.

[0048] In one embodiment of the present invention, the converter of the frequency ratio generator includes a digital-to-analog converter tuned to generate an excitation signal based on the divided signal. The digitally controlled frequency divider is easier to implement and can be easily controlled. The resonator is an analog component. Adding a DAC between the digitally controlled frequency divider and the resonator offers the advantage of combining two advantageous partial solutions in the digital and analog domains, respectively.

[0049] In one embodiment of the present invention, the comparator is - A scaler that is tuned to produce a scaled signal, which is a frequency ratio signal scaled by a scaling factor, and / or - Includes a shifter that is tuned to produce a shifted signal, which is a scaled signal that has been shifted by the shift value. The comparison signal is based on the shifted signal.

[0050] A controlled oscillator typically has an input for controlling the controlled frequency of a controlled signal. The input signal supplied to the input of the controlled oscillator is based on a comparison signal. Depending on the embodiment, other signals can be combined with the comparison signal, such as by adding, subtracting, dividing, and multiplying it. The comparison signal can also be manipulated, such as by filtering, before it becomes the input signal. Typically, when the input to the controlled oscillator is zero, the controlled frequency will have a specific ground frequency or center frequency. Any deviation from zero in the positive or negative direction will result in a positive or negative frequency change, respectively. Applying scalers and shifters provides the option to manipulate the signal so that it is suitable as an input signal for the most common controlled oscillators. Furthermore, scalers and shifters offer the advantage of introducing an additional offset. An additional offset can be used, for example, in telecommunications systems that require some additional space to insert signaling into a bitstream.

[0051] A controlled oscillator can be implemented in many different embodiments. The controlled oscillator can be a voltage-controlled oscillator and optionally have an output from a DAC that provides a signal for the control input of the voltage-controlled oscillator. The controlled oscillator can also be a fully digital PLL.

[0052] In one embodiment of the present invention, the frequency generator is - A phase acquisition circuit that is tuned to generate a phase difference signal based on the phase difference between a controlled frequency and a reference signal having a reference frequency, - Includes a PLL that is tuned to generate an offset signal based on a phase difference signal, The controlled frequency is also based on an offset signal.

[0053] Adding a PLL, preferably a digital PLL, allows for tracking the phase and frequency of an external signal having a specific frequency. The external signal may have considerable phase jitter, such as a carrier wave for telecommunications protocols. The frequency generator can, advantageously, produce a very stable controlled signal with a very stable controlled frequency. The controlled frequency is typically controlled so that it can be used as a reference while receiving communications carried by a carrier wave.

[0054] An advantage of this embodiment, when implemented in most of the digital domain, is that the frequency generator allows various noise sources, such as external signals, resonators, and controlled oscillators, to be identified and at least partially compensated for through the architecture of the frequency generator's loop, particularly loop filters. For example, a resonator is typically affected by temperature, causing changes in resonance over a range of tens of kHz. Meanwhile, a controlled oscillator typically generates phase noise over a range of hundreds of kHz, or even hundreds of MHz, which can be due to Fermi's sea, Brownian motion, etc.

[0055] Resonators and controlled oscillators are typically components implemented in the analog domain. While most frequency generators, advantageously implemented in the digital domain, may require dedicated hardware implementation, it is also possible for part of the implementation to be done in software.

[0056] Loops containing resonators or oscillators generally conform to the Barkhausen criterion. The Barkhausen criterion includes the following constraints: 1. The absolute value of the loop gain is equal to 1; and 2. The phase shift of the loop is 2πx;

number

[0057] The Barkhausen criterion typically imposes additional design constraints on the resonator loop. Loops conforming to the Barkhausen criterion are typically difficult to design and introduce additional phase noise. Typically, loops that include conventional amplifiers to conform to the Barkhausen criterion introduce considerable phase noise and consume considerable power. A controlled oscillator is the only element in a frequency generator that can conform to the Barkhausen criterion. Therefore, this embodiment offers the advantages of low power consumption and minimal phase noise introduction.

[0058] In further embodiments of the present invention, If a shift value is included, the shift value is an offset signal, or If a filtered comparison signal is included, the filtered comparison signal is indirectly based on the offset signal.

[0059] In the first option, the offset signal is supplied through an outer loop filter, whereas in the second option, the offset signal is not supplied through an outer loop filter. In the context of this text, the terms directly and indirectly based on the signal mean whether the input signal contributes to the resulting signal or contributes through the loop, respectively. The first option advantageously limits the number of filters in the system. The second option advantageously allows the offset signal to be added to the signal controlling the controlled oscillator, filtered or unfiltered. The filter applied to the offset signal can advantageously be designed to suit the specific needs for filtering the offset signal. This is particularly advantageous because the offset signal typically has noise in the hundreds of kHz or even hundreds of MHz band, with the controlled oscillator as the primary noise source, while the filtered comparison signal typically has noise in the tens of Hz band, with the resonator as the primary noise source.

[0060] According to another aspect of the present invention, a method for generating a controlled signal having a controlled frequency, - A step of receiving a resonant signal having a first resonant frequency from a resonator, - A step of providing a first ratio signal that shows a first frequency ratio signal between a controlled frequency and a first resonant frequency, - A step of generating a first phase difference signal (155) based on a first frequency phase difference between a first divided frequency and a first resonant frequency, - A step of filtering a first phase difference signal to generate a first frequency ratio signal, - A step of basing the frequency ratio on a first frequency ratio signal, - A step of providing the target ratio, - A step of generating a comparison signal based on a comparison of the frequency ratio with the target ratio, - A step of generating a controlled signal having a controlled frequency based on a comparison signal, - A step of generating a first divided signal (115) having a first divided frequency which is a controlled frequency divided substantially by a first frequency ratio signal, - A step of generating an excitation signal (129) having a first divided frequency based on a first divided signal, wherein the excitation signal is provided to a resonator for excitation of the resonator, - Includes the step of outputting a controlled signal, A first frequency ratio generator loop is formed by the first divided signal, the first phase difference signal, and the first frequency ratio signal. A second frequency ratio generator loop is formed by the first divided signal, excitation signal, resonator, resonant signal, first phase difference signal, and first frequency ratio signal. The filtering step filters the first phase difference signal, thereby preventing instability in the frequency ratio generator loop.

[0061] According to another aspect of the present invention, the frequency generator system is - A frequency generator chip including a frequency generator according to any of the above embodiments, - A resonator for connecting to a frequency generator chip for the purpose of generating a resonant signal, and - Includes an oscillator for connection to a controlled oscillator circuit for the purpose of generating an oscillating signal.

[0062] According to another aspect of the present invention, in a computer program product including a computer-readable medium having computer-readable code embodied internally, the computer-readable code, when executed by a suitable computer or processor, allows the computer or processor to perform the method in one embodiment of the present invention. - A step of providing a first ratio signal, - Steps to generate a comparison signal, - A step of generating a controlled signal, - A step of outputting an excitation signal, - It is configured to perform the steps of outputting a controlled signal.

[0063] According to another aspect of the present invention, a computer program product includes a computer-readable medium having computer-readable code embodied therein, wherein the computer-readable code, when executed by a suitable computer or processor, is configured such that the computer or processor performs a method specified in one embodiment of the present invention.

[0064] The present invention will become clearer and more evident by referring to the embodiments described as examples in the following description and by referring to the accompanying drawings. [Brief explanation of the drawing]

[0065] [Figure 1] This diagram schematically shows a first embodiment of a frequency generator. [Figure 2] This diagram schematically shows a second embodiment of the frequency generator. [Figure 3] This figure schematically shows a first embodiment of a frequency ratio generator. [Figure 4] This figure schematically shows a second embodiment of the frequency ratio generator. [Figure 5] This diagram schematically shows a third embodiment of the frequency ratio generator. [Figure 6] This diagram schematically shows a subsystem for compensating for the effects of temperature. [Figure 7] This diagram schematically shows a subsystem for compensating for the effects of temperature and hysteresis. [Figure 8] This is a schematic diagram illustrating one embodiment of a computer program product.

[0066] The diagram is purely illustrative and is not drawn to scale. In the diagram, elements corresponding to elements already described may have the same reference number. [Explanation of symbols]

[0067] 100…Frequency ratio generator of the first embodiment, 101…Frequency ratio generator of the second embodiment, 102…Frequency ratio generator of the third embodiment, 104…First input signal, 105…Third input signal, 106…Fourth input signal, 107…(First) control signal, 108…Second control signal, 109…Third control signal, 110…(First) control frequency divider, 111…Second control frequency divider, 112…Third control frequency divider, 115…(First) divided signal, 116…Second divided signal, 117…Third divided signal, 120…Additional Calculator, 121…Added signal, 125…Digital-to-analog converter (DAC), 129…Excitation signal, 130…Resonator, 135…Second input signal, 140…Analog-to-digital converter (ADC), 145…Second digital signal, 150…(First) frequency phase detector, 151…Second frequency phase detector, 152…Third frequency phase detector, 155…(First) phase difference signal, 156…Second phase difference signal, 157…Third phase difference signal, 160…(First) loop filter, 161…Second loop filter, 162…Third loop filter 310... Subsystem of the first embodiment, 200... Subsystem of the second embodiment, 210... First circuit including a resonator, 211... Second circuit including a resonator, 220... (First) divider, 221... Second divider, 225... First display, 226... Second display, 230... Subtractor, 235... Subtracted signal, 300... Frequency generator of the first embodiment, 301... Frequency generator of the second embodiment, 310... Comparator, 311... Target ratio, 312 ...Frequency ratio signal, 315...Comparison signal, 320...Outer loop filter, 321...Filtered comparison signal, 330...Controlled oscillator circuit, 331...Controlled signal, 340...Phase acquisition circuit, 341...Reference signal, 345...Phase difference signal, 350...Digital PLL, 355...Offset signal, 356...Adder, 357...Oscillator control signal, 1000...Computer program product, 1010...Computer-readable medium, 1020...Computer-readable code [Modes for carrying out the invention]

[0068] [Detailed description of exemplary embodiments] The following figures may illustrate various embodiments. These embodiments can be combined to achieve enhanced or improved technical effects. These combined embodiments may be explicitly mentioned, suggested, or implicitly described throughout this text.

[0069] Figure 1 schematically shows a first embodiment of the frequency generator 300. The frequency generator includes frequency ratio generators 100, 101, 102, a comparator 310, and a controlled oscillator 330.

[0070] The frequency ratio generator has a controlled frequency 331 as its input. The controlled frequency is the generated frequency and therefore effectively the output of the frequency generator. The frequency ratio generator provides a frequency ratio signal 312.

[0071] A frequency ratio generator includes a resonator. The frequency ratio generator determines the ratio between a controlled frequency and the resonant frequency of the resonator. Furthermore, the frequency ratio generator can determine the ratio between two resonant frequencies of the resonator, where at least one of those resonant frequencies is an overtone frequency. Typically, the resonator changes with respect to temperature and exhibits the effects of hysteresis. The frequency ratio signal can be stabilized or compensated for temperature. The frequency ratio signal can be stabilized or compensated for hysteresis. The frequency ratio signal can be stabilized or compensated for any other effects in the frequency ratio generator, or in the resonator or any other component in the frequency generator.

[0072] The comparator takes a frequency ratio signal and a target ratio 311 as inputs. The target ratio typically has a predefined value or is selected from a set of predefined values. The predefined value is typically determined by the manufacturer, preferably by in-line characterization, during the manufacturing of the frequency ratio generator or resonator. The comparator compares the frequency ratio signal and the target ratio and provides a comparison signal 315 as an output, which is the result of this comparison. Typically, the comparison between the frequency ratio signal and the target ratio is performed by subtraction.

[0073] The controlled oscillator takes a signal based on a comparison signal as its input. The input signal may be a filtered comparison signal with offset 357, a filtered comparison signal 321, a comparison signal, or any other signal based on a comparison signal. The output of the controlled oscillator is a controlled frequency 331.

[0074] A controlled oscillator is typically an oscillator with a center frequency. The oscillator is typically highly stable with respect to hysteresis. Typically, when the oscillator control signal is 0, the controlled frequency is equal to the center frequency. Any change in the oscillator control signal, whether negative or positive, changes the controlled frequency. The change in the controlled frequency is typically linear over a predefined range. Scaling and shifting to obtain a suitable signal as input for the controlled oscillator are advantageously performed in a comparator. The controlled oscillator can be implemented using varicaps, LC networks, or entirely in the digital domain.

[0075] The frequency generator optionally includes an outer loop filter 320. The outer loop filter takes a comparison signal as input. The outer loop filter outputs a filtered comparison signal 321. The outer loop filter filters the comparison signal, thereby preventing instability in the outer loop. The outer loop is formed by at least a frequency ratio generator, a comparator, an outer loop filter, and a controlled oscillator.

[0076] The frequency generator optionally includes an adder 356. The adder takes a filtered comparison signal, a comparison signal, or a signal based on a comparison signal as its first input. The adder takes an offset signal 355 as its second input. The adder adds the two input signals to provide an added signal. The oscillator control signal may be equal to or based on the added signal. This offset signal may be used to shift the added signal to a range suitable as input for a controlled oscillator. The offset signal may also be used to introduce an offset on the oscillator control signal to control a controlled frequency. The offset signal may also be used to introduce an offset, typically a temporal offset, on the oscillator control signal to control the phase of a controlled frequency.

[0077] Assume that the frequency ratio generator is stable and provides a zero-offset signal. Furthermore, assume that the controlled frequency is slightly too high. The frequency ratio generator will output a frequency ratio signal representing the ratio between the resonant frequency of the resonator and the controlled frequency. This frequency ratio will be slightly too high. A comparator will compare the target ratio to the frequency ratio and conclude that the frequency ratio is slightly too high. The result of this comparison will be shown in the comparison signal. Typically, the comparison signal will be slightly too low compared to its desired settling point. An optional outer loop filter may filter the comparison signal. If the outer loop filter includes integration, the error in the controlled frequency can be reduced to zero. A signal based on the comparison signal is provided to the controlled oscillator. The controlled oscillator will respond to the slightly too low signal based on the slightly too low comparison signal by lowering the controlled frequency, thereby stabilizing the controlled frequency to the desired frequency. The controlled frequency is at least partially determined by the setting of the target ratio. An optional offset signal provides an additional means for controlling the controlled frequency. The offset signal can be injected before or after an optional outer loop filter in the loop.

[0078] The embodiment of the present invention shown in Figure 1 may use the embodiment of the frequency ratio generator shown in Figure 3.

[0079] The embodiment of the present invention shown in Figure 1 can be used in combination with the embodiment of the frequency ratio generator shown in Figure 4 and the subsystem shown in Figure 6 to provide a temperature-compensated frequency generator. Furthermore, if the rest of the frequency generator is implemented in the digital domain as much as possible, the frequency generator is particularly insensitive to temperature fluctuations.

[0080] An embodiment of the present invention shown in Figure 1 can be used in combination with the embodiment of the frequency ratio generator shown in Figure 5 and the subsystem shown in Figure 7 to provide a frequency generator compensated for temperature and hysteresis. The frequency generator is particularly insensitive to temperature fluctuations and hysteresis if the frequency ratio generator is compensated for temperature and hysteresis and the rest of the frequency generator is implemented in the digital domain as much as possible.

[0081] Figure 2 schematically shows a second embodiment of the frequency generator 301. This frequency generator includes the elements, signals, and features of the first embodiment. Furthermore, this frequency generator includes a phase acquisition circuit 340 and a PLL 350.

[0082] The phase acquisition circuit has a controlled signal having a controlled frequency and a reference signal 341 having a reference frequency as inputs. The phase acquisition circuit identifies the phase difference between the controlled frequency and the reference frequency and outputs this difference as a phase difference signal 345.

[0083] The phase acquisition block can be implemented as a counter, where one input is used as a clock signal to count zero crossings of the other signal. The number of crossings is related retrospectively to the phase between the signals.

[0084] A PLL takes a controlled signal and a phase difference signal as inputs. The PLL generates a phase-locked signal based on the controlled signal and the phase difference signal. The phase-locked signal may appear as an offset signal 355. The PLL is preferably a digital PLL or a fully digital PLL. The controlled frequency signal is typically used as a clock input to the digital PLL.

[0085] By adding a phase acquisition circuit and a digital PLL, the phase of the controlled frequency is locked to the phase of the reference frequency. This embodiment is typically used to track a remotely generated reference frequency and then locally stabilize this reference frequency, so that the local reference in the form of a controlled frequency exhibits extremely low frequency jitter. Thus, this frequency generator compensates for or removes any disturbances injected between the source of the reference signal and the frequency generator. Illustrative applications can be found in telecommunications such as smartphones or satellite phones, printed circuit boards such as larger printed circuit boards, systems synchronized with atomic clocks, navigation systems, and the like.

[0086] The scenario described above to illustrate the stabilization function of the outer loop can be applied in a similar manner to the embodiment of the frequency generator shown in Figure 2.

[0087] Furthermore, assume that the frequency ratio generator is stable and provides a zero-offset signal. Also, assume that the controlled frequency lags slightly behind the reference signal. The phase acquisition block will detect the phase difference between the controlled frequency and the reference frequency. The PLL will filter the phase difference signal, typically using a high Q factor, to represent the phase difference. The resulting signal from the PLL will be injected into the outer loop as an offset signal to increase the controlled frequency. As soon as the phase acquisition circuit detects no phase difference between the two frequencies, the phase difference signal will indicate a lack of phase difference. The resulting signal from the PLL, injected into the outer loop as an offset signal, will decrease the controlled frequency, remaining in phase with the reference signal. Therefore, The phase of the controlled frequency is locked to the phase of the reference signal. Typically, filtering of the PLL with a high Q value removes phase jitter in the reference signal. Therefore, this embodiment offers the advantage of providing a controlled frequency with low, for example, very low phase jitter. Thus, this frequency generator makes it possible to remove any disturbances (such as jitter) from the reference frequency in order to provide a local control signal with a controlled frequency that is very stable and has low phase jitter.

[0088] The embodiment of the present invention shown in Figure 2 may use the embodiment of the frequency ratio generator shown in Figure 3.

[0089] An embodiment of the present invention shown in Figure 2 can be used in combination with the embodiment of the frequency ratio generator shown in Figure 4 and the subsystem shown in Figure 6 to provide a temperature-compensated frequency generator. The frequency generator is particularly insensitive to temperature fluctuations if the frequency ratio generator is temperature-compensated and the rest of the frequency generator is implemented in the digital domain as much as possible.

[0090] An embodiment of the present invention shown in Figure 2 can be used in combination with the embodiment of the frequency ratio generator shown in Figure 5 and the subsystem shown in Figure 7 to provide a frequency generator compensated for temperature and hysteresis. The frequency generator is particularly insensitive to temperature fluctuations and hysteresis if the frequency ratio generator is compensated for temperature and hysteresis and the rest of the frequency generator is implemented in the digital domain as much as possible.

[0091] Figure 3 schematically shows a first embodiment of the frequency ratio generator 100. The frequency ratio generator includes a controlled frequency divider 110, a frequency phase detector 150, and an inner loop filter 160. The controlled frequency divider may also be labeled as the first controlled frequency divider. The frequency phase detector may also be labeled as the phase detector, the first phase detector, or the first frequency phase detector. The inner loop filter may also be labeled as the first inner loop filter, the first loop filter, or the loop filter.

[0092] The controlled frequency divider takes a first input signal 104 and a control signal 107 as inputs and provides a divided signal 115 as an output. Typically, the first input signal is the controlled signal 331. The control signal may also be labeled as the first control signal. The divided signal may also be labeled as the first divided signal. The first input signal is a periodic signal having a first frequency, typically the controlled frequency. The control signal is typically a signal with a large amount of energy at a lower frequency, such as substantially close to 0 Hz.

[0093] A controlled frequency divider generates divided signals. These divided signals are periodic signals with divided frequencies. The divided frequencies are related to a first frequency based on the magnitude of the control signal. The magnitude can be the amplitude, the value, or any other characteristic of the signal that represents a measurement. In the case where the control signal is an analog signal, the magnitude is typically the amplitude. In the case where the control signal is a digital signal, the magnitude is typically the value. Typically, the relationship between the input and output of a controlled frequency divider is:

[0094]

number

[0095] The phase detector takes the divided signal and a second input signal 135 as inputs and provides a first phase difference signal 155 as an output. The second input signal is a periodic signal having a second frequency. The first phase difference signal may also be labeled as a phase difference signal.

[0096] The magnitude of the phase difference signal is related to the phase difference between the divided frequency and the second frequency. Typically, depending on the implementation of the phase detector, the magnitude of the phase difference signal may have its minimum value at a phase difference of 0 degrees, -90 degrees, or 90 degrees.

[0097] A loop filter takes a phase difference signal as input and provides a control signal as output. A loop filter is typically a low-pass filter. The loop filter stabilizes a loop or feedback loop formed by a control frequency divider, the divided signal, a frequency phase detector, a phase difference signal, the loop filter, and the control signal. The first control signal may be output as a frequency ratio signal 312.

[0098] Assume the first frequency remains unchanged. Furthermore, assume the divided frequency is slightly higher than the second frequency, and that the divided signal and the second input signal are in phase. The phase detector will detect the increasing phase difference between the two signals because the second input signal will begin to lag behind the divided signal. As the phase difference increases, the magnitude of the phase difference signal will increase. Due to some delay, attenuation, and / or reduction resulting from its implementation as a low-pass filter, the loop filter will increase the magnitude of the control signal. This increase in the control signal will cause the first frequency to be divided by a larger magnitude, and therefore a larger number, resulting in a lower divided frequency. Thus, any difference in frequency between the second frequency and the divided frequency will be reduced and / or minimized with the negative feedback loop. Furthermore, since the divided frequency tracks the second frequency, the magnitude of the control signal will represent the ratio between the first frequency and the second frequency.

[0099] In another scenario, assume that the first frequency is increasing. Furthermore, assume that the second frequency is stable. Since the first frequency is increasing and the magnitude of the control signal is stable, the divided frequency will increase. The phase detector will detect the increasing phase difference between the two signals because the second input signal will begin to lag behind the divided signal. As the phase difference increases, the magnitude of the phase difference signal will increase. The loop filter will increase the magnitude of the control signal, along with some delay, attenuation, and / or reduction due to its implementation as a low-pass filter. The increase in the control signal will cause the first frequency to be divided by a larger magnitude, and therefore a larger number, providing a lower divided frequency, which will essentially be the divided frequency before the increase in the first frequency. Thus, no matter how the first frequency changes, the divided frequency will remain essentially the same as the second frequency due to the negative feedback loop. Furthermore, since the divided frequencies track the second frequency, the magnitude of the control signal will represent the ratio between the first and second frequencies, and in this situation, that ratio increases. They will likely continue to do so.

[0100] Typically, since both the first and second frequencies are changing, the above scenarios can be combined.

[0101] To obtain an initial lock, the divided frequencies must be relatively close to the second frequency, such as the resonant frequency of the resonator generating the second frequency; otherwise, the locking procedure to obtain the initial lock may become extremely complex and time-consuming. If the first or second frequency, or a combination of the first and second frequencies, moves faster than the resonator loop can track, the lock may be lost. Preferably, the first frequency should not change too quickly in order to allow for even faster changes in the second frequency. Slow frequency movements of the first and second frequencies over a relatively wide range allow the lock to be maintained. Fast frequency movements of the first and second frequencies over a relatively narrow range also allow the lock to be maintained.

[0102] For some circuits, the frequency range is known. Combining this knowledge with the circuit allows for the selection of resonators and other elements in the loop to maintain lock during operation. As a rule of thumb, if the dynamic frequency tracking of the loop is slower than the combination of the first and second frequency changes, the lock will be lost.

[0103] Figure 4 schematically shows a second embodiment of the frequency ratio generator 101. This circuit includes all the features described with respect to Figure 3. This circuit may further include a second control frequency divider 111, an adder 120, a DAC 125, a resonator 130, an ADC 140, a second phase detector 151, and a second loop filter 161.

[0104] The first control frequency divider 110 takes the first input signal 105 and the first control signal 108 as inputs and provides the first divided signal 115 as an output. The second control frequency divider takes the third input signal 105 and the second control signal 108 as inputs and provides the second divided signal 116 as an output. The adder takes the first and second divided signals as inputs and provides the added signal 121 as an output. This added signal is the sum of the first and second divided signals.

[0105] An optional DAC takes the summed signal as input and provides an excitation signal 129 suitable for resonating the resonator as output. This offers the advantage of having many of the circuit's functions in the digital domain, while only requiring a single DAC to provide the excitation signal, which is typically an analog signal, to the resonator, which is typically a crystal or crystal oscillator. Furthermore, frequency dividers are typically implemented in the digital domain and offer the advantages of ease of implementation and the introduction of limited phase noise. The introduction of limited phase noise is substantially due to the fact that controlled digital fractional frequency dividers have a higher granularity compared to integer frequency dividers.

[0106] In an alternative embodiment, two DACs are present at the respective inputs of the adder, thereby making the adder an analog adder. In yet another alternative embodiment, the circuit does not have a DAC in the loop. In yet another embodiment, a DAC is located between the output of the first loop filter and the first control frequency divider, preferably a second DAC is located between the output of the second loop filter and the second control frequency divider.

[0107] The optional ADC takes the second input signal as input and provides a digital second signal 145 as output. This has many of the functions of the circuit in the digital domain. This offers the advantage of requiring only a single ADC to receive a second input signal, which is typically an analog signal, from a resonator, which is typically a crystal. In an alternative embodiment, two ADCs are located between their respective phase sensors and loop filters. In yet another embodiment, two ADCs are located between their respective loop filters and control frequency dividers.

[0108] The first frequency phase detector 150 takes the first divided signal 115 and the second digital signal 145 as inputs and provides the first phase difference signal 155 as an output. The second frequency phase detector 151 takes the second divided signal 116 and the second digital signal 145 as inputs and provides the second phase difference signal 156 as an output. The first loop filter 160 takes the first phase difference signal as an input and provides the first control signal 107 as an output. The second loop filter 161 takes the second phase difference signal as an input and provides the second control signal 108 as an output.

[0109] Typically, the first divided frequency and the second divided frequency are separate frequencies, both of which are the resonant frequencies of the resonator. Thus, this resonator is typically one that allows simultaneous resonance at separate frequencies. Typically, this resonator is a quartz crystal resonator. Furthermore, typically, at least one of the resonances is a harmonic resonance, and preferably both resonances are harmonic resonances.

[0110] As previously mentioned, the temperature behavior may differ if at least one of the first and second divided frequencies is selected as a harmonic frequency. The temperature can vary within the range of -40°C to +125°C. Within this range, the temperature gradient with respect to a particular harmonic can vary.

[0111] Either a first control signal or a second control signal can be selected as the frequency ratio signal. Typically, the first and second control signals are combined to compensate for temperature effects, particularly temperature effects on the resonator. This combination is then provided as the frequency ratio signal as an output. Using this combination, it is possible to select the control signal that changes the least with respect to a particular temperature. As shown in and described in relation to Figure 6, the first and second control signals may be divided to provide a temperature indicator that allows compensation for any temperature effects of the frequency generator, frequency ratio generator, and especially the resonator. The compensation is typically predefined, for example, by providing the frequency ratio generator with settings for estimating compensation coefficients for the first and second control signals, and / or preferably for other signals inside the frequency ratio generator, in order to provide a compensated frequency ratio signal.

[0112] Figure 5 schematically shows a third embodiment of the frequency ratio generator 102. This frequency ratio generator includes all the features described with respect to Figure 4. This circuit may further include a third controlled frequency divider 112, a third phase detector 152, and a third loop filter 162.

[0113] The first control frequency divider 110 takes the first input signal 105 and the first control signal 108 as inputs and provides the first divided signal 115 as an output. The second control frequency divider takes the third input signal 105 and the second control signal 108 as inputs and provides the second divided signal 116 as an output. The third control frequency divider takes the fourth input signal 106 and the third control signal 109 as inputs and provides the third divided signal 117 as an output. The adder takes the first, second, and third divided signals as inputs and provides the added signal 121 as an output. This added signal is the sum of the first, second, and third divided signals.

[0114] The first frequency phase detector 150 takes the first divided signal 115 and the digital second signal 145 as inputs and provides the first phase difference signal 155 as an output. The second frequency phase detector 151 takes the second divided signal 116 and the digital second signal 145 as inputs and provides the second phase difference signal 156 as an output. The third frequency phase detector 152 takes the third divided signal 117 and the digital third signal 145 as inputs and provides the third phase difference signal 157 as an output. The first loop filter 160 takes the first phase difference signal as an input and provides the first control signal 107 as an output. The second loop filter 161 takes the second phase difference signal as an input and provides the second control signal 108 as an output. The third loop filter 162 takes the third phase difference signal as an input and provides the third control signal 109 as an output.

[0115] Typically, the first divided frequency, the second divided frequency, and the third divided frequency are separate frequencies, all of which are the resonant frequencies of the resonator. Thus, this resonator is typically one that allows simultaneous resonance at separate frequencies. Typically, this resonator is a quartz resonator. Furthermore, typically, at least two of the resonances are harmonic resonances, and preferably, all of the resonances are harmonic resonances.

[0116] As previously mentioned, the temperature behavior may differ if at least one of the first and second divided frequencies is selected as a harmonic frequency. The temperature can vary within the range of -40°C to +125°C. Within this range, the temperature gradient with respect to a particular harmonic can vary.

[0117] One of the first, second, or third control signals can be selected as the frequency ratio signal. Typically, the first, second, and / or third control signals are combined to compensate for the effects of temperature and / or hysteresis, particularly on the resonator. This combination is then provided as the frequency ratio signal as the output. Using this combination, it is possible to select the control signal that changes the least with respect to a particular temperature. As shown in and described in relation to Figure 7, it is possible to split the first and second control signals to provide a first representation, and it is possible to split the first and third control signals to provide a second representation. Both or at least one of them make it possible to compensate for any temperature effects on the frequency generator, frequency ratio generator, and especially the resonator. Both representations, when subtracted, make it possible to compensate for any hysteresis effects on the frequency generator, frequency ratio generator, and especially the resonator. Compensation is typically predefined during manufacturing, for example, by providing the frequency ratio generator with settings for estimating compensation coefficients for first, second, and third control signals, and / or, preferably, other signals within the frequency ratio generator, in order to provide a compensated frequency ratio signal.

[0118] Figure 6 schematically shows a subsystem 200 for compensating for temperature effects. This subsystem includes frequency ratio generators 101, 102 according to any embodiment of the present invention, which include resonators and provide a control signal 107 and a second control signal 108, as shown in Figures 1 and 2. This subsystem further includes a control signal divider 220 which is tuned to generate a divided control signal 225 based on the division of the control signal by the second control signal. The divided control signal is a temperature indicator 225. Using this temperature indicator, it is possible to apply temperature compensation to the frequency ratio signal in a separate unit to provide a temperature-compensated frequency ratio.

[0119] Figure 7 shows a schematic representation of subsystem 201 for compensating for the effects of temperature and hysteresis. As shown, the system includes a frequency ratio generator 211 according to any embodiment of the present invention, which includes a resonator and provides a control signal 107, a second control signal 108, and a third control signal 109. The subsystem further includes a first control signal divider 220 which is tuned to produce a divided control signal 225 based on the division of a control signal by the second control signal. The first divided control signal is a first temperature indicator 225. The system further includes a second control signal divider 221 which is tuned to produce a second divided control signal 226 based on the division of a control signal by a third control signal. The second divided control signal is a second temperature indicator 226.

[0120] The system optionally includes a subtractor 230 tuned to generate a subtracted signal 235 based on subtracting a second divided control signal from a first divided control signal. Typically, the first and second divided control signals have separate lowest temperature activity. The subtracted signal is a temperature and / or hysteresis indicator. Based on this subtracted signal, the first, second, and / or third control signals can be compensated for the effects of temperature and hysteresis, particularly from the resonator. Furthermore, it is possible to compensate the frequency ratio signal for temperature and hysteresis in a separate unit to provide a frequency ratio compensated for temperature and hysteresis.

[0121] The embodiment shown in Figure 4, coupled with the feature that this embodiment is tuned to resonate at two separate resonant frequencies (selected such that these resonant frequencies have separate activity dips, each having first and second control signals indicating first and second ratios), would be suitable for measuring temperature changes in a resonator, preferably a quartz resonator. In the context of this application, the separate lowest temperature activity is the minimum value that shows their smallest frequency change at separate or individual temperatures. This smallest change may be related to a different frequency of another signal. This embodiment offers the advantage that it is possible to measure the temperature change of the resonator over the entire temperature range with high accuracy. Another advantage is that dividing the first ratio by the second ratio provides a ratio that is independent of the first frequency. Thus, any temperature-dependent variation of the first frequency can be eliminated.

[0122] Furthermore, the embodiment in Figure 4 may be extended to include a third loop, as shown in Figure 5. The third loop includes a third control frequency divider 112, a third phase detector 152, and a third loop filter 162, all of which are tuned in a similar manner to those relating to the first and second loops. Furthermore, this embodiment is extended with a first control signal divider that generates a first divided control signal by dividing a control signal by a second control signal. Furthermore, this embodiment is extended with a second control signal divider that generates a second divided control signal by dividing a control signal by a third control signal. Furthermore, this embodiment is extended with a subtractor that is tuned to generate a subtracted signal based on subtracting a second divided control signal from a first divided control signal, the subtracted signal indicating the temperature of the resonator. Furthermore, at least the first and second divided control signals have separate minimum temperature activity.

[0123] This embodiment offers the advantage of being able to measure the temperature change of the resonator over the entire temperature range with high accuracy. Another advantage is that the division of the ratio provides divided ratios, and these ratios are independent of the first frequency. Therefore, any temperature-dependent variation of the first frequency can be eliminated or at least minimized. Furthermore, any time-dependent behavior of the resonator that changes the resonant frequency, such as hysteresis, can be compensated for.

[0124] The frequency measurement technique used enables a measurement accuracy of approximately 0.1 ppb at a speed of 1 k samples / second. This allows the system to measure small temperature changes in resonators such as quartz crystals at a stable primary frequency. Small temperature changes can be in the millikelvin range. Furthermore, the system is typically capable of responding to changes quite quickly.

[0125] In one embodiment of a frequency ratio generator, an offset is added to the phase difference signal. This allows the loop to be locked at different angles. For example, if the frequency phase detector has a minimum output signal for a 0-degree phase shift on its input, the offset will lock the loop at angles other than 0 degrees. For example, if the frequency phase detector has a minimum output signal for a 90-degree phase shift on its input, the offset will lock the loop at angles other than 90 degrees.

[0126] In one embodiment, a resonator such as a crystal oscillator, crystal, or crystal resonator may be used, which is read indirectly. This indirect reading may introduce a phase shift. This introduced phase shift can be corrected by introducing the offset described above.

[0127] Typically, one or more of the signals can be normalized to simplify further calculations using those signals.

[0128] In one variant of the frequency generator, the frequency ratio signal is based on a first phase difference signal, a second phase difference signal, and / or a third phase difference signal. The selection from each of these phase difference signals, or their respective weights, may also be based on a first control signal, a second control signal, and / or a third control signal. This variant offers the advantage that the inner loop signal is filtered only by the inner loop filter, and the outer loop signal is filtered only by the outer loop filter. Each of these filters, particularly the outer loop, can be tuned to the specific requirements of that loop. The requirements for each loop typically involve balancing loop stability with agility to external changes.

[0129] In one variant of the frequency generator, the outer loop filter 320 and the adder 356 are swapped, so that the offset signal also passes through the outer loop filter. This variant has the advantage of further filtering the offset signal and thus further stabilizing it. The original configuration, as shown in Figure 2, has the advantage that by filtering the signal through the PLL, it is possible to reach or approach an optimal balance between the stability and agility of the loop formed by the controlled oscillator and the PLL, and also the loop formed by the controlled oscillator, the phase acquisition circuit, and the PLL.

[0130] To facilitate the collaboration between the various blocks mentioned throughout this explanation and shown in the diagrams, it may be necessary to scale and / or shift signals and / or inverted signals. For example, frequency ratio signals and target ratios are typically inverted in a comparator to become comparison signals, which are then ready to be processed by the rest of the system.

[0131] Figure 8 schematically illustrates one embodiment of a non-temporary computer-readable storage medium comprising a computer program product 1000, a computer-readable medium 1010, and / or a computer-readable code 1020. The computer-readable code implements the methods referred to throughout this description of the present invention.

[0132] A signal can be a periodic signal. A periodic signal repeats after every period. The number of repetitions per second is equal to the frequency. Furthermore, a signal can have a maximum magnitude, such as amplitude or value, mean signal level, and RMS level. In the context of this text, a signal can be an analog signal, such as a voltage signal, current signal, power signal, and / or energy signal. In the context of this text, a signal can also be a digital signal representing a voltage signal, current signal, power signal, and / or energy signal. A frequency ratio is a frequency ratio signal.

[0133] A controlled frequency divider can be a digital controlled frequency divider. A controlled frequency divider can be a controlled multiplex frequency divider. A controlled multiplex frequency divider provides an output signal having an output frequency equal to the input frequency of the input signal divided by n, where n is the number of elements in set N. The formula is as follows:

[0134]

number

[0135] Alternatively, the controlled frequency divider can be a controlled fraction divider. The formula is as follows:

[0136]

number

[0137]

number

[0138] An exemplary embodiment of a digitally controlled multi-frequency divider is one in which the divider switches between division numbers N and N+1. A requirement is that when the divided signals are fed to a resonator, this resonator has a reasonable quality Q. By switching between N and N+1, fractions such as N+3 / 4 or N+5 / 7 are possible.

[0139] Such a digitally controlled multi-frequency divider can be implemented by adding an accumulator with a configurable maximum value. In the N+3 / 4 example, an accumulator with a maximum capacity of 4 and a number to be repeatedly added of 3 will have carries in three of the four cycles. Whenever a carry exists, the divider should divide by the number N+1, and at all other times, the divider should divide by N. This technique can be classified as shaping.

[0140] Higher-order shaping can be achieved by adding another accumulator and a small differentiator. As a result, with respect to higher-order shaping, the digitally controlled frequency divider can divide by N-1, N, N+1, or N+2. Higher-order shaping causes the spectral behavior to exhibit a steeper roll-off, thereby reducing the loop Noise is reduced in this area. Higher-order shaping offers the circuit the advantage of a more stable frequency ratio.

[0141] A Digital-to-Time Converter (DTC) can be used to shift the edges of a signal, such as the output of a digitally controlled multiplexer. A digitally controlled multiplexer divides N, which alternates in some pattern, by dividing it by N+1, while a DTC interpolates the edges so that they are almost perfectly aligned in time. Therefore, a DTC can reduce the jitter introduced in the circuit, offering the advantage of a more stable circuit and / or frequency ratio.

[0142] The two methods described above are digitally controlled multifrequency dividers and DTCs, and they have distinct characteristics in terms of noise and accuracy. A digitally controlled multifrequency divider provides divided signals, and its accuracy, optionally, depends on loop filtering and rejection, and, if present, on resonators. On the other hand, a DTC offers much better initial accuracy but has the disadvantage of adding a large spectrally significant noise component. It is not easy to determine which advantage or disadvantage is dominant, because these advantages and disadvantages vary depending on the behavior of other circuit components, especially other circuit components in the loop, and the signals supplied to the circuit.

[0143] A frequency phase detector can be a frequency mixer, analog multiplier, digital circuit, or logic circuit configured as a phase detector. A frequency phase detector, phase detector, or phase detector generates an output signal such as a phase difference signal, which represents the difference in phase between two input signals, such as between a divided signal and a second input signal. Depending on the type of frequency phase detector, the input signals may need to be phase-shifted to provide an output signal that can be used to perform a lock-on with respect to a loop. As an example, a logic circuit phase detector made from ex-OR logic gates typically locks a loop with a 90° phase shift between input signals.

[0144] Inner and outer loop filters stabilize the inner and outer loops, respectively. They can further stabilize their respective loops by considering the input signals supplied to the frequency ratio generator and frequency generator, respectively. If a resonator is present, the inner and outer loop filters can further stabilize the circuit by considering the behavior of the resonator. Inner and outer loop filters can be first-order or multi-order filters. Loop filters are typically low-pass filters. The cutoff frequency of a loop filter is typically a balance between the accuracy and speed of disturbance correction in the circuit. A lower cutoff frequency allows less jitter through each loop filter, thus providing higher accuracy, while a higher cutoff frequency provides a faster response to changes in the circuit, such as temperature changes. The behavior of each loop lock in the circuit can also be influenced by the choice of each loop filter, particularly its cutoff frequency. An important factor in designing loop filters is considering the loop gain. Each loop filter is typically implemented as a PID controller.

[0145] A resonator has a fundamental frequency, which is the lowest frequency at which it resonates. Furthermore, a resonator can resonate at harmonic frequencies, and the harmonic frequencies follow the following relationship.

[0146]

number

[0147] Furthermore, resonators can resonate at harmonic frequencies, and these harmonic frequencies follow the following relationship.

[0148]

number

[0149] The resonant frequencies of a crystal, crystal oscillator, or crystal resonator can be even-order harmonics or odd-order harmonics and their associated overtones. Typically, odd-order harmonics and their associated overtones are used to make the crystal resonate.

[0150] Please note that the diagram is purely illustrative and not drawn to scale. In the diagram, elements corresponding to elements already described may have the same reference number.

[0151] It will be understood that the present invention also applies to computer programs adapted to carry out the present invention, in particular computer programs on or within a carrier. The program may be in the form of source code, object code, code intermediate source, and partially compiled forms of object code, or any other form suitable for use in carrying out the method according to the present invention. It will also be understood that such programs may have many different architectural designs. For example, program code that carries out the functionality of the method or system according to the present invention may be subdivided into one or more subroutines. Many different ways of distributing functionality among these subroutines will be apparent to those skilled in the art. These subroutines may be stored together in a single executable file to form a self-contained program. Such an executable file may contain computer executable instructions, such as processor instructions and / or interpreter instructions (e.g., Java interpreter instructions). Alternatively, one or more or all of the subroutines may be stored in at least one external library file and linked statically or dynamically, for example at runtime, to the main program. The main program includes at least one call to at least one of the subroutines. Subroutines may also include function calls to each other. One embodiment relating to a computer program product includes computer executable instructions corresponding to each of at least one processing stage of the methods described herein. These instructions can be subdivided into subroutines and / or stored in one or more files that can be linked statically or dynamically. Another embodiment relating to a computer program product includes computer executable instructions corresponding to each of at least one means of the systems and / or products described herein.These instructions can be subdivided into subroutines and / or stored in one or more files that can be linked statically or dynamically.

[0152] A computer program carrier can be any entity or device capable of carrying that program. For example, the carrier could be a ROM, such as a CD-ROM or semiconductor ROM, or a magnetic recording medium, such as a hard disk. This may include data storage such as the above. Furthermore, the carrier may be a transmittable carrier such as an electrical or optical signal, which may be transmitted via an electrical or optical cable, or by wireless or other means. If the program is embodied in such a signal, the carrier may consist of such a cable or other device or means. Alternatively, the carrier may be an integrated circuit in which the program is embedded, which is adapted to perform or used in performing the relevant method.

[0153] It should be noted that the embodiments described above are illustrative rather than limiting of the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, no reference symbols placed between parentheses should be construed as limiting the claims. The use of the verb "comprise" and its conjugations does not preclude the existence of elements or stages other than those described in the claims. The articles "a" or "an" preceding an element do not preclude the existence of multiple such elements. The invention may be carried out using hardware comprising several individual elements and using a appropriately programmed computer. In device claims listing several means, some of these means may be embodied by one of the same items of hardware. The mere fact that certain measures are listed in different dependent claims does not imply that it is impossible for combinations of these measures to be used advantageously.

[0154] Examples, embodiments, or optional features, whether shown as non-limiting or not, should not be understood as limiting the claimed invention. Item 1 A frequency generator (300, 301) for generating a controlled signal (331) having a controlled frequency, It includes frequency ratio generators (100, 101, 102) that are tuned to produce frequency ratios, and the frequency ratio generators (100, 101, 102) An input device configured to receive the controlled signal, A first controlled frequency divider (110) is tuned to generate a first divided signal (115) having a first divided frequency which is the controlled frequency divided substantially by a first frequency ratio signal, A converter tuned to generate an excitation signal (129) having the first divided frequencies based on the first divided signal, wherein the excitation signal is provided to the resonator for excitation of the resonator, A resonator (130) tuned to generate a resonant signal having a first resonant frequency, wherein the resonator is excited by the excitation signal, A first frequency phase detector (150) is tuned to generate a first phase difference signal (155) based on a first frequency phase difference between the first divided frequency and the first resonant frequency, A first inner loop filter (160) is tuned to generate the first frequency ratio signal, Includes an output device configured to provide a frequency ratio signal (312) based on a first frequency ratio signal (107) indicating the frequency ratio between the controlled frequency and the first resonant frequency, The first control frequency divider, the first divided signal, the first frequency phase detector, the first phase difference signal, the first inner loop filter, and the first frequency ratio signal form a first frequency ratio generator loop. The first control frequency divider, the first divided signal, the converter, the excitation signal, the resonator, the resonant signal, the first frequency phase detector, the first phase difference signal, the first inner loop filter, and the first frequency ratio signal form a second frequency ratio generator loop. The first inner loop filter filters the first phase difference signal, thereby preventing instability in the frequency ratio generator loop. The frequency generator further, A comparator (310) is adjusted to generate a comparison signal (315) based on a comparison of the frequency ratio with a target ratio (311), A frequency generator (300, 301) including a controlled oscillator circuit (330) which is tuned to generate the controlled signal having the controlled frequency based on the comparison signal. Item 2 Includes an outer loop filter (320) which is tuned to generate a filtered comparison signal (321) based on the comparison signal, The controlled frequency is determined based on the filtered comparison signal. The frequency ratio generator, the comparator, the comparison signal, the outer loop filter, the filtered comparison signal, the controlled oscillator, and the controlled signal form the outer loop. The outer loop filter filters the comparison signal, thereby preventing instability in the outer loop. The frequency generator described in item 1. Item 3 The comparator includes a subtractor which is tuned to provide the comparison signal based on subtracting the target ratio from the frequency ratio, and / or The comparator includes a divider which is tuned to provide the comparison signal based on dividing the frequency ratio by the target ratio, A frequency generator as described in item 1 or 2. Item 4 The frequency ratio generator, A second controlled frequency divider (111) is tuned to generate a second divided signal (116) having a second divided frequency which is the controlled frequency divided by a second frequency ratio signal (108), A second frequency phase detector (151) is tuned to generate a second phase difference signal (156) based on a second frequency phase difference between the second divided frequency and the second resonant frequency, A second inner loop filter (161) is tuned to generate a second frequency ratio signal representing the second frequency ratio based on the second phase difference signal, An adder (120) is configured to generate an added signal (121) supplied to the converter, wherein the added signal has the first divided frequency and the second divided frequency, The resonator includes a temperature compensator for compensating for changes in the resonant frequency of the resonator, and the temperature compensator is An input device configured to receive the first frequency ratio and the second frequency ratio, A first divider (220) is adjusted to generate a first division value based on the division of the first frequency ratio by the second frequency ratio, A computer, preferably including a lookup table, is configured to calculate a compensation coefficient based on one or more values ​​from a group consisting of the first phase difference signal, the second phase difference signal, the first frequency ratio, and the first division value. A redresser is adjusted to generate the frequency ratio by correcting the signal based on one or more of a group consisting of the first phase difference signal, the second phase difference signal, and the first frequency ratio, using the compensation coefficient. The excitation signal is based on the summed signal, A third frequency ratio generator loop is formed by the second control frequency divider, the second divided signal, the second frequency phase detector, the second phase difference signal, the second inner loop filter, and the second frequency ratio signal. A fourth frequency ratio generator loop is formed by the second control frequency divider, the second divided signal, the converter, the excitation signal, the resonator, the resonant signal, the second frequency phase detector, the second phase difference signal, the second inner loop filter, and the second frequency ratio signal. The frequency generator according to item 3, wherein the second inner loop filter filters the second phase difference signal, thereby preventing instability in the frequency ratio generator loop. Item 5 The frequency ratio generator, Includes a selector that is adjusted to select one or more of the groups consisting of the first phase difference signal, the second phase difference signal, and the first frequency ratio, based on one or more values ​​from the group consisting of the first frequency ratio and the first division value. The frequency generator according to item 4, wherein the redresser is adjusted to generate the frequency ratio based on correcting the selected frequency ratio using the compensation coefficient. Item 6 The frequency ratio generator, A third controlled frequency divider (112) is tuned to generate a third divided signal (117) having a third divided frequency which is the controlled frequency divided substantially by a third frequency ratio signal, A third frequency phase detector (152) is tuned to generate a third phase difference signal (157) based on a third frequency phase difference between the third divided frequency and the third resonant frequency, The system includes a third inner loop filter (162) which is tuned to generate a third frequency ratio signal representing the third frequency ratio based on the third phase difference signal, The summed signal also has the third divided frequency, The input device of the temperature compensator is further configured to receive the third frequency ratio, The aforementioned temperature compensator further, Includes a second divider (221) which is adjusted to generate a second division value based on the division of the first frequency ratio by the third frequency ratio, If dependent on item 5, the selector is further configured to make a selection based on one or more values ​​from an extended group consisting of the third phase difference signal, the second frequency ratio, and the third frequency ratio, as well as the second frequency ratio, the third frequency ratio, and the second division value. The computer is further configured to calculate the compensation coefficient based on one or more values ​​from the group expanded by the third phase difference signal, the second frequency ratio, the third frequency ratio, and the second division value. The redresser is adjusted to generate the frequency ratio based on correcting the selected frequency ratio using the compensation coefficient, A fifth frequency ratio generator loop is formed by the third control frequency divider, the third divided signal, the third frequency phase detector, the third phase difference signal, the third inner loop filter, and the third frequency ratio signal. A sixth frequency ratio generator loop is formed by the third control frequency divider, the third divided signal, the converter, the excitation signal, the resonator, the resonant signal, the third frequency phase detector, the third phase difference signal, the third inner loop filter, and the third frequency ratio signal. The frequency generator according to item 4 or 5, wherein the third inner loop filter filters the third phase difference signal, thereby preventing instability in the frequency ratio generator loop. Item 7 The selector of the frequency ratio generator Selecting one of the groups consisting of the first frequency ratio, the second frequency ratio, and the third frequency ratio, wherein the selected ratio is based on one or more values ​​from the group consisting of the first frequency ratio, the second frequency ratio, the third frequency ratio, the first division value, and the second division value, or The frequency generator according to item 6, which is configured to select two or more weighted combinations of the first frequency ratio, the second frequency ratio, and the third frequency ratio, wherein the weighted combinations are configured to select based on one or more values ​​from a group consisting of the first frequency ratio, the second frequency ratio, the third frequency ratio, the first division value, and the second division value. Item 8 The first division value is based solely on the first frequency ratio signal and the second frequency ratio signal. The second division value is based solely on the first frequency ratio signal and the third frequency ratio signal. The selector is configured to select one or more of a limited group consisting of the first phase difference signal, the second phase difference signal, and the third phase difference signal, and / or The computer is configured to calculate a compensation coefficient based on one or more values ​​from a limited group consisting of the first division value and the second division value. A frequency generator as described in any one of items 4 through 7. Item 9 The frequency generator according to any one of items 1 to 8, wherein the frequency ratio generator includes an analog-to-digital converter (140) which is tuned to generate a digital resonant signal (145) based on the resonant signal, and the digital resonant signal is supplied to at least the first frequency phase detector. Item 10 A frequency generator according to any one of items 1 to 9, wherein the converter of the frequency ratio generator includes a digital-to-analog converter (125) which is tuned to generate the excitation signal based on the divided signal. Item 11 The aforementioned comparator, A scaler adjusted to produce a scaled signal which is the frequency ratio signal scaled by a scaling factor, and / or Includes a shifter which is adjusted to generate a shifted signal, which is the scaled signal that has been shifted by a shift value, The comparison signal is a frequency generator according to any one of items 1 to 10, based on the shifted signal. Item 12 A phase acquisition circuit (340) is configured to generate a phase difference signal (345) based on the phase difference between the controlled frequency and a reference signal (341) having a reference frequency, Includes a PLL (350) which is adjusted to generate an offset signal (355) based on the phase difference signal, The controlled frequency is also based on the offset signal. A frequency generator as described in any one of items 1 through 11. Item 13 If at least item 11 is dependent, then the shift value is the offset signal, or If at least item 2 is dependent, the filtered comparison signal is indirectly based on the offset signal. The frequency generator described in item 12. Item 14 A method for generating a controlled signal having a controlled frequency, The steps include receiving a resonant signal having a first resonant frequency from a resonator, The steps include providing a first ratio signal that indicates a first frequency ratio between the controlled frequency and the first resonant frequency, A step of generating a first phase difference signal (155) based on a first frequency phase difference between a first divided frequency and a first resonant frequency, To generate the first frequency ratio signal, the first phase difference signal is filtered, This prevents instability in the frequency ratio generator loop, A step of basing the frequency ratio on the first frequency ratio signal, Steps include providing the target ratio, A step of generating a comparison signal based on a comparison of the frequency ratio with the target ratio, A step of generating the controlled signal having the controlled frequency based on the comparison signal, A step of generating a first divided signal (115) having a first divided frequency which is substantially the controlled frequency divided by the first frequency ratio signal, A step of generating an excitation signal (129) having the first divided frequencies based on the first divided signal, wherein the excitation signal is provided to the resonator for excitation of the resonator; The step includes outputting the controlled signal, The first divided signal, the first phase difference signal, and the first frequency ratio signal form a first frequency ratio generator loop. A second frequency ratio generator loop is formed by the first divided signal, the excitation signal, the resonator, the resonance signal, the first phase difference signal, and the first frequency ratio signal. A method wherein the filtering step filters the first phase difference signal, thereby preventing instability in the frequency ratio generator loop. Item 15 A frequency generator chip including a frequency generator as described in any one of items 1 through 14, A resonator connected to the frequency generator chip for the purpose of generating the aforementioned resonant signal, An oscillator for connecting to the controlled oscillator circuit for the purpose of generating an oscillation signal and A frequency generator system including a frequency generator. Item 16 A computer program product (1000) comprising a computer-readable medium (1010) having a computer-readable code (1020) embodied internally, wherein the computer-readable code, when executed by a suitable computer or processor, comprises the steps of the computer or processor providing a first ratio signal according to the method described in item 14, Steps to base the frequency ratio, The steps include generating a comparison signal and The steps include generating the controlled signal, The steps include outputting an excitation signal and A computer program product (1000) configured to perform the step of outputting the controlled signal. Item 17 A computer program product (1000) comprising a computer-readable medium (1010) having computer-readable code (1020) embodied internally, wherein the computer-readable code is configured such that, when executed by a suitable computer or processor, the computer or processor is caused to perform the method described in item 14.

Claims

1. A frequency generator (300, 301) for generating a controlled signal (331) having a controlled frequency, Includes frequency ratio generators (100, 101, 102) which are tuned to produce frequency ratios, An input device configured to receive the controlled signal, A first controlled frequency divider (110) is configured to generate a first divided signal (115) having a first divided frequency which is the controlled frequency divided by a first frequency ratio signal indicating a first frequency ratio, A converter tuned to generate an excitation signal (129) having the first divided frequencies based on the first divided signal, wherein the excitation signal is provided to the resonator for excitation of the resonator, The resonator (130) is tuned to generate a resonant signal having a first resonant frequency, and is excited by the excitation signal, A first frequency phase detector (150) is configured to generate a first phase difference signal (155) based on a first frequency phase difference between the first divided frequency and the first resonant frequency, A first inner loop filter (160) tuned to generate the first frequency ratio signal, Includes an output device configured to provide a frequency ratio signal (312) based on a first frequency ratio signal (107) indicating the frequency ratio between the controlled frequency and the first resonant frequency, The first control frequency divider, the first divided signal, the first frequency phase detector, the first phase difference signal, the first inner loop filter, and the first frequency ratio signal form a first frequency ratio generator loop. A second frequency ratio generator loop is formed by the first control frequency divider, the first divided signal, the converter, the excitation signal, the resonator, the resonant signal, the first frequency phase detector, the first phase difference signal, the first inner loop filter, and the first frequency ratio signal. The first inner loop filter filters the first phase difference signal, thereby preventing instability in the first frequency ratio generator loop and the second frequency ratio generator loop. The frequency generator further, A comparator (310) is adjusted to generate a comparison signal (315) based on a comparison between a target ratio (311) and the frequency ratio, Includes a controlled oscillator circuit (330) which is tuned to generate the controlled signal having the controlled frequency based on the comparison signal, Frequency generators (300, 301).

2. Includes an outer loop filter (320) which is tuned to generate a filtered comparison signal (321) based on the comparison signal, The controlled frequency is determined based on the filtered comparison signal. The frequency ratio generator, the comparator, the comparison signal, the outer loop filter, the filtered comparison signal, the controlled oscillator circuit, and the controlled signal form the outer loop. The outer loop filter filters the comparison signal, thereby preventing instability in the outer loop. The frequency generator according to claim 1.

3. The comparator includes a subtractor that is tuned to provide the comparison signal based on subtracting the target ratio from the frequency ratio, and / or The comparator includes a divider which is tuned to provide the comparison signal based on dividing the frequency ratio by the target ratio, The frequency generator according to claim 1 or 2.

4. The frequency ratio generator, A second controlled frequency divider (111) is adjusted to generate a second divided signal (116) having a second divided frequency which is the controlled frequency divided by a second frequency ratio signal (108) indicating the second frequency ratio of the resonator, A second frequency phase detector (151) is tuned to generate a second phase difference signal (156) based on a second frequency phase difference between the second divided frequency and the second resonant frequency of the resonator, A second inner loop filter (161) is tuned to generate a second frequency ratio signal indicating the second frequency ratio of the resonator based on the second phase difference signal, An adder (120) is configured to generate an added signal (121) supplied to the converter, wherein the added signal has the first divided frequency and the second divided frequency, The resonator includes a temperature compensator for compensating for changes in the resonant frequency of the resonator, and the temperature compensator is An input device configured to receive the first frequency ratio signal and the second frequency ratio signal, A first divider (220) is configured to generate a first division value based on the division of the first frequency ratio of the first frequency ratio signal by the second frequency ratio, A computer, which includes a lookup table, is configured to calculate a compensation coefficient based on one or more values ​​from a group consisting of the first phase difference signal, the second phase difference signal, the first frequency ratio signal, and the first division value. A redresser is included which is adjusted to generate the frequency ratio by correcting the signal based on one or more of a group consisting of the first phase difference signal, the second phase difference signal, and the first frequency ratio signal, using the compensation coefficient, The excitation signal is based on the summed signal, A third frequency ratio generator loop is formed by the second control frequency divider, the second divided signal, the second frequency phase detector, the second phase difference signal, the second inner loop filter, and the second frequency ratio signal. A fourth frequency ratio generator loop is formed by the second control frequency divider, the second divided signal, the converter, the excitation signal, the resonator, the resonant signal, the second frequency phase detector, the second phase difference signal, the second inner loop filter, and the second frequency ratio signal. The frequency generator according to claim 3, wherein the second inner loop filter filters the second phase difference signal, thereby preventing instability in the third frequency ratio generator loop and the fourth frequency ratio generator loop.

5. The frequency ratio generator, Includes a selector that is adjusted to select one or more of the groups consisting of the first phase difference signal, the second phase difference signal, and the first frequency ratio signal based on one or more values ​​from the group consisting of the first frequency ratio signal and the first division value, The frequency generator according to claim 4, wherein the redresser is adjusted to generate the frequency ratio based on correcting the frequency ratio selected using the compensation coefficient.

6. The frequency ratio generator, A third controlled frequency divider (112) is configured to generate a third divided signal (117) having a third divided frequency which is the controlled frequency divided by a third frequency ratio signal indicating a third frequency ratio, A third frequency phase detector (152) is tuned to generate a third phase difference signal (157) based on a third frequency phase difference between the third divided frequency and the third resonant frequency of the resonator, The system includes a third inner loop filter (162) which is tuned to generate the third frequency ratio signal, which represents the third frequency ratio, based on the third phase difference signal. The summed signal also has the third divided frequency, The input device of the temperature compensator is further configured to receive the third frequency ratio, The aforementioned temperature compensator further, Includes a second divider (221) which is adjusted to generate a second division value based on the division of the first frequency ratio by the third frequency ratio, If dependent on claim 5, the selector is further configured to make selections based on one or more values ​​from an extended group consisting of the third phase difference signal, the second frequency ratio, and the third frequency ratio, as well as from the group consisting of the second frequency ratio, the third frequency ratio, and the second division value. The computer is further configured to calculate the compensation coefficient based on one or more values ​​from the group expanded by the third phase difference signal, the second frequency ratio, the third frequency ratio, and the second division value. The redresser is adjusted to generate the frequency ratio based on correcting the selected frequency ratio using the compensation coefficient, A fifth frequency ratio generator loop is formed by the third control frequency divider, the third divided signal, the third frequency phase detector, the third phase difference signal, the third inner loop filter, and the third frequency ratio signal. A sixth frequency ratio generator loop is formed by the third control frequency divider, the third divided signal, the converter, the excitation signal, the resonator, the resonant signal, the third frequency phase detector, the third phase difference signal, the third inner loop filter, and the third frequency ratio signal. The frequency generator according to claim 4 or 5, wherein the third inner loop filter filters the third phase difference signal, thereby preventing instability in the fifth frequency ratio generator loop and the sixth frequency ratio generator loop.

7. The selector of the frequency ratio generator Selecting one of the groups consisting of the first frequency ratio, the second frequency ratio, and the third frequency ratio, wherein the selected ratio is based on one or more values ​​from the group consisting of the first frequency ratio, the second frequency ratio, the third frequency ratio, the first division value, and the second division value, or The frequency generator according to claim 6, wherein the frequency generator is configured to select two or more weighted combinations of the first frequency ratio, the second frequency ratio, and the third frequency ratio, wherein the weighted combinations are configured to select based on one or more values ​​from a group consisting of the first frequency ratio, the second frequency ratio, the third frequency ratio, the first division value, and the second division value.

8. The first division value is based solely on the first frequency ratio signal and the second frequency ratio signal. The second division value is based solely on the first frequency ratio signal and the third frequency ratio signal. The selector is configured to select one or more of a limited group consisting of the first phase difference signal, the second phase difference signal, and the third phase difference signal, and / or The computer is configured to calculate a compensation coefficient based on one or more values ​​from a limited group consisting of the first division value and the second division value. The frequency generator according to claim 6 or 7.

9. The frequency ratio generator includes an analog-to-digital converter (140) which is tuned to generate a digital resonant signal (145) based on the resonant signal, and the digital resonant signal is supplied to at least the first frequency phase detector. The frequency generator according to any one of claims 1 to 8, wherein the converter of the frequency ratio generator includes a digital-to-analog converter (125) which is tuned to generate the excitation signal based on the divided signal.

10. The aforementioned comparator, A scaler adjusted to generate a scaled signal which is the frequency ratio signal scaled by a scaling factor, and / or Includes a shifter which is adjusted to generate a shifted signal, which is the scaled signal that has been shifted by a shift value, The frequency generator according to any one of claims 1 to 9, wherein the comparison signal is based on the shifted signal.

11. A phase acquisition circuit (340) is configured to generate a phase difference signal (345) based on the phase difference between the controlled frequency and a reference signal (341) having a reference frequency, The PLL (350) is adjusted to generate an offset signal (355) based on the phase difference signal, The controlled frequency is also based on the offset signal. A frequency generator according to any one of claims 1 to 10.

12. If at least one of the claims is dependent on claim 10, the shift value is the offset signal, or If at least dependent on claim 2, the filtered comparison signal is indirectly based on the offset signal. The frequency generator according to claim 11.

13. A method for generating a controlled signal having a controlled frequency, The steps include receiving a resonant signal having a first resonant frequency from a resonator, The steps include providing a first frequency ratio signal that indicates a first frequency ratio between the controlled frequency and the first resonant frequency, A step of generating a first phase difference signal (155) based on a first frequency phase difference between a first divided frequency and a first resonant frequency, The steps include filtering the first phase difference signal to generate the first frequency ratio signal, thereby preventing instability in the first frequency ratio generator loop and the second frequency ratio generator loop, A step of basing the frequency ratio on the first frequency ratio signal, Steps include providing the target ratio, A step of generating a comparison signal based on a comparison of the frequency ratio with the target ratio, A step of generating the controlled signal having the controlled frequency based on the comparison signal, A step of generating a first divided signal (115) having a first divided frequency which is the controlled frequency divided by the first frequency ratio signal, A step of generating an excitation signal (129) having the first divided frequencies based on the first divided signal, wherein the excitation signal is provided to the resonator for excitation of the resonator; The step includes outputting the controlled signal, The first divided signal, the first phase difference signal, and the first frequency ratio signal form the first frequency ratio generator loop. The second frequency ratio generator loop is formed by the first divided signal, the excitation signal, the resonator, the resonance signal, the first phase difference signal, and the first frequency ratio signal. A method wherein the filtering step filters the first phase difference signal, thereby preventing instability in the first frequency ratio generator loop and the second frequency ratio generator loop.

14. A frequency generator chip including the frequency generator described in any one of claims 1 to 12, A resonator connected to the frequency generator chip for the purpose of generating the aforementioned resonant signal, An oscillator for connecting to the controlled oscillator circuit for the purpose of generating an oscillation signal, A frequency generator system including a frequency generator.

15. A computer-readable medium (1010) that records computer-readable code (1020) that is materialized internally, wherein when the computer-readable code is executed by a computer or processor, the computer or processor performs the method according to claim 13. The steps include providing a first ratio signal, Steps to base the frequency ratio, The steps include generating a comparison signal and The steps include generating the controlled signal, The steps include outputting an excitation signal and It is configured to perform the step of outputting the controlled signal, The computer-readable code is configured such that, when executed by a computer or processor, the computer or processor is caused to perform the method according to claim 13, in a computer-readable medium (1010).

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